Cylinder construction for air cooled engines



1936- I 'c. 5. BROWN 2,062,393

v CYLINDER CONSTRUCTION FOR AIR COOLED ENGINES Filed Sept. 11, 1935 5 Sheets-Sheet i ATTORNEYS,

Dec. 1, 1936. G, 8 BROWN 2,062,393

CYLINDER'CONSTRUCTION FOR AIR COOLED ENGINES Filed Sept. 11, 1935 3 Sheets-Sheet 2.

Q 'VENTOR. F 4 Z%%M ATTORNEYS Dec. 1, 1936. 2,062,393

CYLINDER CONSTRUCTION FOR AIR COOLED ENGINES c. s. BROWN Filed Sept. 11, 1955 3 Sheets-Sheet 5 BY I W V ATTORI EYS Patented Dec. 1, 1936 UNITED STATES PTENT OFFICE CYLINDER CONSTRUCTIQN FOR AIR COOLED ENGINES This invention relates to air cooled combustion engines and has for its object a cylinder construction by which not only is the heat quickly absorbed from the interior or bore of the cylinder, but also excess heat accumulated temporarily in a mass or block of metal from which it is absorbed by a comparatively gentle air current, so that the liability of excessive heating or overheating of the cylinder is eliminated under all conditions, ordinary and extraordinary.

It further has for its object a cylinder construction in which the valves, particularly the exhaust valve, is located in the barrel portion of the cylinder, and a mass of metal provided to quickly conduct the heat away from the exhaust valve and port to avoid overheating of the exhaust valve.

It further has for its object an air cooled internal combustion engine which cools under ordinary and extraordinary conditions without the use of a fan requiring considerable power, but on the contrary is cooled under ordinary and extraordinary conditions by a gentle air current.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1 is a longitudinal sectional view of a cylinder construction embodying my invention.

Figure 2 is a sectional view on line 2-2, Figure 1.

Figure 3 is a side elevation looking to the left in Figure 1.

Figure 4 is an inverted face view of the detached head block.

Figure 5 is a fragmentary sectional View showing the preferred joint between the heat radiating fins and the head block.

Figure 6 is a plan view of two cylinder blocks, each formed with a pair of cylinders, illustrating the relative arrangement of the cylinders in a four cylinder engine, or in one bank of an eight V-type cylinder engine.

Heretofore, air cooled engines, such as are used in motor vehicles have been cooled by a forced air current created by a fan or blower consuming considerable power from the crankshaft of the engine. The cooling of the cylinders is dependent upon the volume and speed of the air passed over the cylinders during a given time. Also, although the amount of air pumped by the fan is dependent upon the speed, to some extent, and the design of the fan, nevertheless the maximum amount of air is not always being delivered when the engine is the hottest, and one of the objects of this invention, is means by which storage is provided for excess heat generated, and uniform cooling is not dependent upon conditions of the air current, but is effected by a moving air not requiring excessive power to keep it in motion.

The cylinder construction includes a barrel block and a head block, the body of each of which is of a metal having relatively high heat conductivity, as aluminum or aluminum alloy, and one of these blocks, preferably, the head, is provided with a mass of metal greater than required to form the ordinary head and give it the required strength, the excess metal providing a storage for excess heat to accumulate that can not be carried ofi immediately by the air under extraordinary running conditions. Ordinarily a head of one-half inch thickness is required to give the required strength to withstand the compression and the shock of the explosions. In this engine, the head has an average thickness of one and one-half or two inches throughout its length and breadth. The excess metal over that required to give strength to the head forms a cooling mass or medium or a temporary storage for excess heat.

This engine is also of the L head type and the barrel block is formed with a mass of metal on one side thereof in which the valve ports are located, particularly the exhaust valve port. This mass of metal around the ports is sufficient todraw the heat out to the outer surface where it can be removed by a gentle air current. Thus, the head block itself can be practically a solid mass of metal, into which the heat from the combustion chamber is quickly absorbed. The mass of the storage block is of such size that the block has the capacity to absorb excess heat away from the combustion chamber and keep the combustion chamber comparatively cool under abnormal conditions, as when pulling up long steep grades.

l designates the barrel block, that here shown being a multiple cylinder block with two cylinder bores 2. The barrel block is formed with heat radiating flanges 3 cast integral therewith and is provided on one side thereof with a mass or integral block of metal 4 in which the intake and exhaust ports 5, 6 are provided, and in which the guides I for the stems 8 of the valves 9 are provided. The valve'9 is substantially the same as any valve in any L head engine, but the mass of metal 4 of relatively high heat conductivity is such as to withdraw the heat and distribute the heat substantially uniformly. It is to be understood that the intake valve is relatively cold and the exhaust valve hot, and. therefore, ordinarily, there would be difierential expansion and contraction or warping of the mass l. By providing a mass 4 of sufficient capacity to absorb the heat, differential expansion and contraction is avoided, due to the fact that the colder parts of the mass of metal of high heat conductivity quickly absorb the heat in the hotter portions.

An L head motor has not been practical in high power air cooled engines, because of the difierential expansion and contraction around the intake and exhaust ports, although L head air cooled engines have been used in smaller types, as motorcycle engines.

Some of the heat radiating fins 3 extend around the ends of the barrel blocks and around the mass 4.

As seen in Figure 3, the exhaust ports 5 are located toward the end of the block, and the intake ports 5 toward the center of the block.

This arrangement is for the purpose of bringing as large an area as possible of the mass 4 and fins 3 adjacent the exhaust ports in contact with the cross air stream, particularly between the pairs of cylinders. The barrel block may or may not be provided with a liner for taking the wear of the piston.

l0 designates the head block, this being common to a plurality of cylinders and being here shown as common to the two cylinders of each block. The head is formed of a metal having comparatively great heat conductivity, as aluminum or aluminum alloy, and is provided with a heat absorbing or storage mass or portions I2, l3 above the base or base portion H proper adjacent the barrel block and in which the combustion chamber M is formed. As here shown, the storage blocks l2, I3 are in step formation relatively to each other and to the base portion I, and the step portions are provided with heat radiating and storage fins, preferably of sheet metal, or of similar metal, as the head block H2. The base of the head block proper is also provided with sheet metal heat radiating fins embedded therein. The fins !5 and I6 project from the riser portions of the step formation of the head block and the fins ll from the edge of the base portion H. Thus, the fins are arranged in series or courses one above the other. The storage portions 12 and I3 extend lengthwise of the head in the form of ridges, as seen in Figure 6. The sheet metal fins make it possible to increase the number of fins used compared with fins cast integral with the head block, and thus greatly increase the heat exchanging area over which the gentle air current passes. The head block is secured to the barrel block in any suitable manner, as by screws I8, extending through the head proper at the side of the heat storage block i2 and into the body of the barrel block, and the fins on the storage block !2 are cut away at H! to provide space for the heads of the screws. Also, the fins H are sometimes split, as at 29 to avoid distortion by unequal cooling. The fins l5, l6, I! are embedded in the head mass during the casting of the head block and the margins thereof embedded in the head. The margins may be embedded in the mass in the usual manner or may be sharpened to a knife edge, as

shown at 2| in Figure 5 to most intimately unite with both a perfect mechanical and thermal union with the mass. Preferably, a wide joint and metallic gasket is provided between the head and the barrel at 22 to provide a good heat conducting joint between the head block and the barrel block.

In operation, the air circulation may be provided in any suitable manner either by the motion of the vehicle through the air, or by a fan. It is usually provided by what is the ordinary propeller type radiator fan in water cooled internal combustion engines. During ordinary running over ordinary roads, the cooling is no problem, but when long steep grades are encountered, ordinarily the air cooled engine gets hotter and hotter to such an extent that it fails to function properly. However, by my invention, the storage blocks absorb the excess heat and owing to its large radiating or cooling surface, dissipates the heat to a gently moving air current, thus keeping the engine temperature down well within eflicient operating limits. When the top of the grade is reached, the excess heat radiates very quickly almost instantly, on the following level or down hill grades.

Thus, in this engine, a heat radiator of sulficient capacity to cool the engine at all times is provided in the engine cylinder construction itself and preferably on the hottest or head portion thereof, so that the volume and velocity of a cooling air current is not relied on. The invention in its broader aspects is comprehended in connection with a different specific form of head in application Serial No. 40,301, filed September 12, 1935, to

which cross reference is made.

What I claim is:-

1. A cylinder construction for internal combustion engines comprising a head block of a metal having relatively high heat conductivity, said head including a mass of metal greater than required to give the required strength to the combustion chamber to provide an excess heat storage block, the body of said storage block being wider at its base than at its top and its outer surface being formed stepped, the body of the storage block being formed with sheet metal heat storage and radiating fins of substantially the same metal as the block and extending from the risers of the step formation.

2. A cylinder construction for an L-head internal combustion engine comprising a barrel block and a head block, the barrel block having a body of metal having relatively high heat conductivity,

and being formed with an offset mass on one side" thereof in which the intake and exhaust ports are formed, the mass of metal around the ports being arranged to conduct the heat away from the ports and equalize the heat throughout the mass, and the head block being formed of a metal having a high heat conductivity and including a mass greater than required to give strength to the combustion chamber, and constituting means for storing excess heat.

3. A cylinder head construction for internal combustion engines and the like, said head comprising a block of metal of relatively high heat conductivity and radiativity and being of such size as to absorb from the combustion chamber excess heat generated by the engine when working under abnormal load conditions, said block tapering in a widthwise direction from its base toward its top.

CHARLES S. BROWN. 

